| 1 | // gold-threads.cc -- thread support for gold |
| 2 | |
| 3 | // Copyright 2006, 2007, 2008 Free Software Foundation, Inc. |
| 4 | // Written by Ian Lance Taylor <iant@google.com>. |
| 5 | |
| 6 | // This file is part of gold. |
| 7 | |
| 8 | // This program is free software; you can redistribute it and/or modify |
| 9 | // it under the terms of the GNU General Public License as published by |
| 10 | // the Free Software Foundation; either version 3 of the License, or |
| 11 | // (at your option) any later version. |
| 12 | |
| 13 | // This program is distributed in the hope that it will be useful, |
| 14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | // GNU General Public License for more details. |
| 17 | |
| 18 | // You should have received a copy of the GNU General Public License |
| 19 | // along with this program; if not, write to the Free Software |
| 20 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| 21 | // MA 02110-1301, USA. |
| 22 | |
| 23 | #include "gold.h" |
| 24 | |
| 25 | #include <cstring> |
| 26 | |
| 27 | #ifdef ENABLE_THREADS |
| 28 | #include <pthread.h> |
| 29 | #endif |
| 30 | |
| 31 | #include "options.h" |
| 32 | #include "parameters.h" |
| 33 | #include "gold-threads.h" |
| 34 | |
| 35 | namespace gold |
| 36 | { |
| 37 | |
| 38 | class Condvar_impl_nothreads; |
| 39 | |
| 40 | // The non-threaded version of Lock_impl. |
| 41 | |
| 42 | class Lock_impl_nothreads : public Lock_impl |
| 43 | { |
| 44 | public: |
| 45 | Lock_impl_nothreads() |
| 46 | : acquired_(false) |
| 47 | { } |
| 48 | |
| 49 | ~Lock_impl_nothreads() |
| 50 | { gold_assert(!this->acquired_); } |
| 51 | |
| 52 | void |
| 53 | acquire() |
| 54 | { |
| 55 | gold_assert(!this->acquired_); |
| 56 | this->acquired_ = true; |
| 57 | } |
| 58 | |
| 59 | void |
| 60 | release() |
| 61 | { |
| 62 | gold_assert(this->acquired_); |
| 63 | this->acquired_ = false; |
| 64 | } |
| 65 | |
| 66 | private: |
| 67 | friend class Condvar_impl_nothreads; |
| 68 | |
| 69 | bool acquired_; |
| 70 | }; |
| 71 | |
| 72 | #ifdef ENABLE_THREADS |
| 73 | |
| 74 | class Condvar_impl_threads; |
| 75 | |
| 76 | // The threaded version of Lock_impl. |
| 77 | |
| 78 | class Lock_impl_threads : public Lock_impl |
| 79 | { |
| 80 | public: |
| 81 | Lock_impl_threads(); |
| 82 | ~Lock_impl_threads(); |
| 83 | |
| 84 | void acquire(); |
| 85 | |
| 86 | void release(); |
| 87 | |
| 88 | private: |
| 89 | // This class can not be copied. |
| 90 | Lock_impl_threads(const Lock_impl_threads&); |
| 91 | Lock_impl_threads& operator=(const Lock_impl_threads&); |
| 92 | |
| 93 | friend class Condvar_impl_threads; |
| 94 | |
| 95 | pthread_mutex_t mutex_; |
| 96 | }; |
| 97 | |
| 98 | Lock_impl_threads::Lock_impl_threads() |
| 99 | { |
| 100 | pthread_mutexattr_t attr; |
| 101 | int err = pthread_mutexattr_init(&attr); |
| 102 | if (err != 0) |
| 103 | gold_fatal(_("pthead_mutextattr_init failed: %s"), strerror(err)); |
| 104 | #ifdef PTHREAD_MUTEXT_ADAPTIVE_NP |
| 105 | err = pthread_mutextattr_settype(&attr, PTHREAD_MUTEX_ADAPTIVE_NP); |
| 106 | if (err != 0) |
| 107 | gold_fatal(_("pthread_mutextattr_settype failed: %s"), strerror(err)); |
| 108 | #endif |
| 109 | |
| 110 | err = pthread_mutex_init (&this->mutex_, &attr); |
| 111 | if (err != 0) |
| 112 | gold_fatal(_("pthread_mutex_init failed: %s"), strerror(err)); |
| 113 | |
| 114 | err = pthread_mutexattr_destroy(&attr); |
| 115 | if (err != 0) |
| 116 | gold_fatal(_("pthread_mutexattr_destroy failed: %s"), strerror(err)); |
| 117 | } |
| 118 | |
| 119 | Lock_impl_threads::~Lock_impl_threads() |
| 120 | { |
| 121 | int err = pthread_mutex_destroy(&this->mutex_); |
| 122 | if (err != 0) |
| 123 | gold_fatal(_("pthread_mutex_destroy failed: %s"), strerror(err)); |
| 124 | } |
| 125 | |
| 126 | void |
| 127 | Lock_impl_threads::acquire() |
| 128 | { |
| 129 | int err = pthread_mutex_lock(&this->mutex_); |
| 130 | if (err != 0) |
| 131 | gold_fatal(_("pthread_mutex_lock failed: %s"), strerror(err)); |
| 132 | } |
| 133 | |
| 134 | void |
| 135 | Lock_impl_threads::release() |
| 136 | { |
| 137 | int err = pthread_mutex_unlock(&this->mutex_); |
| 138 | if (err != 0) |
| 139 | gold_fatal(_("pthread_mutex_unlock failed: %s"), strerror(err)); |
| 140 | } |
| 141 | |
| 142 | #endif // defined(ENABLE_THREADS) |
| 143 | |
| 144 | // Class Lock. |
| 145 | |
| 146 | Lock::Lock() |
| 147 | { |
| 148 | if (!parameters->options().threads()) |
| 149 | this->lock_ = new Lock_impl_nothreads; |
| 150 | else |
| 151 | { |
| 152 | #ifdef ENABLE_THREADS |
| 153 | this->lock_ = new Lock_impl_threads; |
| 154 | #else |
| 155 | gold_unreachable(); |
| 156 | #endif |
| 157 | } |
| 158 | } |
| 159 | |
| 160 | Lock::~Lock() |
| 161 | { |
| 162 | delete this->lock_; |
| 163 | } |
| 164 | |
| 165 | // The non-threaded version of Condvar_impl. |
| 166 | |
| 167 | class Condvar_impl_nothreads : public Condvar_impl |
| 168 | { |
| 169 | public: |
| 170 | Condvar_impl_nothreads() |
| 171 | { } |
| 172 | |
| 173 | ~Condvar_impl_nothreads() |
| 174 | { } |
| 175 | |
| 176 | void |
| 177 | wait(Lock_impl* li) |
| 178 | { gold_assert(static_cast<Lock_impl_nothreads*>(li)->acquired_); } |
| 179 | |
| 180 | void |
| 181 | signal() |
| 182 | { } |
| 183 | |
| 184 | void |
| 185 | broadcast() |
| 186 | { } |
| 187 | }; |
| 188 | |
| 189 | #ifdef ENABLE_THREADS |
| 190 | |
| 191 | // The threaded version of Condvar_impl. |
| 192 | |
| 193 | class Condvar_impl_threads : public Condvar_impl |
| 194 | { |
| 195 | public: |
| 196 | Condvar_impl_threads(); |
| 197 | ~Condvar_impl_threads(); |
| 198 | |
| 199 | void |
| 200 | wait(Lock_impl*); |
| 201 | |
| 202 | void |
| 203 | signal(); |
| 204 | |
| 205 | void |
| 206 | broadcast(); |
| 207 | |
| 208 | private: |
| 209 | // This class can not be copied. |
| 210 | Condvar_impl_threads(const Condvar_impl_threads&); |
| 211 | Condvar_impl_threads& operator=(const Condvar_impl_threads&); |
| 212 | |
| 213 | pthread_cond_t cond_; |
| 214 | }; |
| 215 | |
| 216 | Condvar_impl_threads::Condvar_impl_threads() |
| 217 | { |
| 218 | int err = pthread_cond_init(&this->cond_, NULL); |
| 219 | if (err != 0) |
| 220 | gold_fatal(_("pthread_cond_init failed: %s"), strerror(err)); |
| 221 | } |
| 222 | |
| 223 | Condvar_impl_threads::~Condvar_impl_threads() |
| 224 | { |
| 225 | int err = pthread_cond_destroy(&this->cond_); |
| 226 | if (err != 0) |
| 227 | gold_fatal(_("pthread_cond_destroy failed: %s"), strerror(err)); |
| 228 | } |
| 229 | |
| 230 | void |
| 231 | Condvar_impl_threads::wait(Lock_impl* li) |
| 232 | { |
| 233 | Lock_impl_threads* lit = static_cast<Lock_impl_threads*>(li); |
| 234 | int err = pthread_cond_wait(&this->cond_, &lit->mutex_); |
| 235 | if (err != 0) |
| 236 | gold_fatal(_("pthread_cond_wait failed: %s"), strerror(err)); |
| 237 | } |
| 238 | |
| 239 | void |
| 240 | Condvar_impl_threads::signal() |
| 241 | { |
| 242 | int err = pthread_cond_signal(&this->cond_); |
| 243 | if (err != 0) |
| 244 | gold_fatal(_("pthread_cond_signal failed: %s"), strerror(err)); |
| 245 | } |
| 246 | |
| 247 | void |
| 248 | Condvar_impl_threads::broadcast() |
| 249 | { |
| 250 | int err = pthread_cond_broadcast(&this->cond_); |
| 251 | if (err != 0) |
| 252 | gold_fatal(_("pthread_cond_broadcast failed: %s"), strerror(err)); |
| 253 | } |
| 254 | |
| 255 | #endif // defined(ENABLE_THREADS) |
| 256 | |
| 257 | // Methods for Condvar class. |
| 258 | |
| 259 | Condvar::Condvar(Lock& lock) |
| 260 | : lock_(lock) |
| 261 | { |
| 262 | if (!parameters->options().threads()) |
| 263 | this->condvar_ = new Condvar_impl_nothreads; |
| 264 | else |
| 265 | { |
| 266 | #ifdef ENABLE_THREADS |
| 267 | this->condvar_ = new Condvar_impl_threads; |
| 268 | #else |
| 269 | gold_unreachable(); |
| 270 | #endif |
| 271 | } |
| 272 | } |
| 273 | |
| 274 | Condvar::~Condvar() |
| 275 | { |
| 276 | delete this->condvar_; |
| 277 | } |
| 278 | |
| 279 | #ifdef ENABLE_THREADS |
| 280 | |
| 281 | // Class Initialize_lock_once. This exists to hold a pthread_once_t |
| 282 | // structure for Initialize_lock. |
| 283 | |
| 284 | class Initialize_lock_once |
| 285 | { |
| 286 | public: |
| 287 | Initialize_lock_once() |
| 288 | : once_(PTHREAD_ONCE_INIT) |
| 289 | { } |
| 290 | |
| 291 | // Return a pointer to the pthread_once_t variable. |
| 292 | pthread_once_t* |
| 293 | once_control() |
| 294 | { return &this->once_; } |
| 295 | |
| 296 | private: |
| 297 | pthread_once_t once_; |
| 298 | }; |
| 299 | |
| 300 | #endif // !defined(ENABLE_THREADS) |
| 301 | |
| 302 | #ifdef ENABLE_THREADS |
| 303 | |
| 304 | // A single lock which controls access to initialize_lock_pointer. |
| 305 | // This is used because we can't pass parameters to functions passed |
| 306 | // to pthread_once. |
| 307 | |
| 308 | static pthread_mutex_t initialize_lock_control = PTHREAD_MUTEX_INITIALIZER; |
| 309 | |
| 310 | // A pointer to a pointer to the lock which we need to initialize |
| 311 | // once. Access to this is controlled by initialize_lock_control. |
| 312 | |
| 313 | static Lock** initialize_lock_pointer; |
| 314 | |
| 315 | // A routine passed to pthread_once which initializes the lock which |
| 316 | // initialize_lock_pointer points to. |
| 317 | |
| 318 | extern "C" |
| 319 | { |
| 320 | |
| 321 | static void |
| 322 | initialize_lock_once() |
| 323 | { |
| 324 | *initialize_lock_pointer = new Lock(); |
| 325 | } |
| 326 | |
| 327 | } |
| 328 | |
| 329 | #endif // !defined(ENABLE_THREADS) |
| 330 | |
| 331 | // Class Initialize_lock. |
| 332 | |
| 333 | Initialize_lock::Initialize_lock(Lock** pplock) |
| 334 | : pplock_(pplock) |
| 335 | { |
| 336 | #ifndef ENABLE_THREADS |
| 337 | this->once_ = NULL; |
| 338 | #else |
| 339 | this->once_ = new Initialize_lock_once(); |
| 340 | #endif |
| 341 | } |
| 342 | |
| 343 | // Initialize the lock. |
| 344 | |
| 345 | bool |
| 346 | Initialize_lock::initialize() |
| 347 | { |
| 348 | // If the lock has already been initialized, we don't need to do |
| 349 | // anything. Note that this assumes that the pointer value will be |
| 350 | // set completely or not at all. I hope this is always safe. We |
| 351 | // want to do this for efficiency. |
| 352 | if (*this->pplock_ != NULL) |
| 353 | return true; |
| 354 | |
| 355 | // We can't initialize the lock until we have read the options. |
| 356 | if (!parameters->options_valid()) |
| 357 | return false; |
| 358 | |
| 359 | // If the user did not use --threads, then we can initialize |
| 360 | // directly. |
| 361 | if (!parameters->options().threads()) |
| 362 | { |
| 363 | *this->pplock_ = new Lock(); |
| 364 | return true; |
| 365 | } |
| 366 | |
| 367 | #ifndef ENABLE_THREADS |
| 368 | |
| 369 | // If there is no threads support, we don't need to use |
| 370 | // pthread_once. |
| 371 | *this->pplock_ = new Lock(); |
| 372 | |
| 373 | #else // !defined(ENABLE_THREADS) |
| 374 | |
| 375 | // Since we can't pass parameters to routines called by |
| 376 | // pthread_once, we use a static variable: initialize_lock_pointer. |
| 377 | // That in turns means that we need to use a mutex to control access |
| 378 | // to initialize_lock_pointer. |
| 379 | |
| 380 | int err = pthread_mutex_lock(&initialize_lock_control); |
| 381 | if (err != 0) |
| 382 | gold_fatal(_("pthread_mutex_lock failed: %s"), strerror(err)); |
| 383 | |
| 384 | initialize_lock_pointer = this->pplock_; |
| 385 | |
| 386 | err = pthread_once(this->once_->once_control(), initialize_lock_once); |
| 387 | if (err != 0) |
| 388 | gold_fatal(_("pthread_once failed: %s"), strerror(err)); |
| 389 | |
| 390 | initialize_lock_pointer = NULL; |
| 391 | |
| 392 | err = pthread_mutex_unlock(&initialize_lock_control); |
| 393 | if (err != 0) |
| 394 | gold_fatal(_("pthread_mutex_unlock failed: %s"), strerror(err)); |
| 395 | |
| 396 | gold_assert(*this->pplock_ != NULL); |
| 397 | |
| 398 | #endif // !defined(ENABLE_THREADS) |
| 399 | |
| 400 | return true; |
| 401 | } |
| 402 | |
| 403 | } // End namespace gold. |